NAME
Class::PObject - Simple framework for programming persistent objects
SYNOPSIS
After loading Class::PObject with "use", we can declare a class:
pobject Person => {
columns => ['id', 'name', 'email'],
datasource => './data'
};
We can also declare the class in its own .pm file:
package Person;
use Class::PObject;
pobject {
columns => ['id', 'name', 'email'],
datasource => './data'
};
We can now create an instance of above Person, fill it with data, and
save it:
$person = new Person();
$person->name('Sherzod');
$person->email('sherzodr[AT]cpan.org');
$new_id = $person->save()
We can access the saved Person later, make necessary changes and save
back:
$person = Person->load($new_id);
$person->name('Sherzod Ruzmetov (The Geek)');
$person->save()
We can load multiple objects as well:
@people = Person->load();
for $person ( @people ) {
printf("[%02d] %s \n", $person->id, $person->name, $person->email)
}
or we can load all the objects based on some criteria and sort the list
by column name in descending order, and limit the results to only the
first 3 objects:
@people = Person->load(
{name => "Sherzod"},
{sort => "name", direction => "desc", limit=>3});
We can also seek into a specific point of the result set:
@people = Person->load(undef, {offset=>10, limit=>10});
DESCRIPTION
Class::PObject is a simple class framework for programming persistent
objects in Perl. Such objects can store themselves into disk, and
restore themselves from disk.
PHILOSOPHY
This section has been moved to Class::PObject::Philosophy.
TODO
Class::PObject is not a tool for solving all the problems of the
Universe. It may be its success rather than its failure. I still want it
to do certain things, for I believe they are right down its alley.
* Multiple object joins
Currently "load()" and "fetch()" methods are used for querying a
single object. It would be ideal if we could select multiple objects
at a time through some *join* syntax.
* Column Indexes
While RDBMS drivers do not need this, db_file, csv and file drivers
will not be suitable for production environment until they do.
Column indexes are needed to retrieve more complex queries much
faster, without having to perform linear search. With aforementioned
drivers (especially file and csv) once number of records increases,
querying objects gets extremely processor intensive if more complex
"load()" and "fetch()" methods are used.
* SET Column types
Currently column types can be configured to be of *HAS-A*
relationship. It would be great if we could specify *HAS-MANY*
relationships. Following syntax is still to be implemented:
pobject Article => {
columns => ['id', 'title', 'authors'],
tmap => {
authors => ['Author']
}
};
Notice, *authors* field is set to be able to hold an array of
*Author* objects.
NOTES
Pobjects try to cache the driver object for more extended periods than
pobject's scope permits them to. So a *global destructor* should be
applied to prevent unfavorable behaviors, especially under persistent
environments, such as mod_perl
Global variables that *may* need to be cleaned up are:
$Class::PObject::Driver::$drivername::__O
Where "$drivername" is the name of the driver used. If more than one
driver is used in your project, more of these variables may exist.
This variable holds particular driver object.
$ClassName::props
Holds the properties for this particular PObject named "$ClassName".
For example, if you created a pobject called *Person*, then it's
properties are stored in global variable "$Person::props".
For example, if our objects were using just a mysql driver, in our main
application we could've done something like:
END {
$Class::PObject::Driver::mysql::__O = undef;
}
DRIVER SPECIFICATIONS
You can learn more about pobject driver specs in the following manuals:
Class::PObject::Driver
Base pobject driver specification. All the drivers are expected to
inherit from this class.
Class::PObject::Driver::DBI
Base pobject driver for all the DBI-related drivers. This inherits
from Class::PObject::Driver, but re-defines certain methods with
those more relevant to DBI drivers.
Class::PObject::Driver::DBM
Base pobject driver for all the DBM-related drivers. It inherits
from Class::PObject::Driver, and re-defines certain methods with
those more relevant to DBM
COLUMN TYPE SPECIFICATIONS
You can learn more about column type specs from Class::PObject::Type,
which is also a base class of all the types.
SEE ALSO
http://poop.sourceforge.net/, although little dated, provides brief
overview of available tools for programming Persistent Objects in Perl.
As of this writing, Class::PObject is still not mentioned.
AUTHOR
Sherzod B. Ruzmetov, , http://author.handalak.com/
COPYRIGHT AND LICENSE
Copyright (c) 2003 Sherzod B. Ruzmetov. All rights reserved.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
2003/09/09 00:11:52